Fuel pump



Jan. 4, 1938. A. BABITCH ET AL FUEL PUMP Filed Nov. 30, 1931 2 sheets-sheet 1 dumm Jan. 4, 1938. A. M. BABITCH ET AL 4,

FUEL PUMP v Filed Nov. 50, 1931 I 2 She tSQSheet J J iw w m w w I r m M I 1 n. m W

jatdozz Patented Jan. 4, 1938 UNITED STATES PATENT OFFICE FUEL PUMP aware Application November 30, 1931, Serial No. 577,922 3 Claims. (01. 103-150) This invention relates to pumps and has been designed as an improved pump for supplying fuel to aninternal combustion engine.

An object of the invention is to simplify the construction of a combined pump and fuel filter.

As a further object the invention aims to prevent overheating and vaporization of fuel in the pump chamber.

Other objects and advantages, such as compactness and economy in manufacture will be understood from the following description.

In the drawings accompanying this description Fig. l is a view in vertical section through the Fig. 2 is a sectional view on line 22 of Fig. 1.

Fig. 3 is a view in perspective of the jointed operating parts.

Fig. 4 is a view partly in elevation and partly in section, the section being substantially on line 44 of Fig. 5, this view representing a modified form.

Fig. 5 is a top plan view of the modification shown in Fig. 4 with parts removed.

Fig. 6 is a section on line 6-3 of Fig. 5.

Referring by reference characters to the drawings, numeral 1 on Fig. l designates a body member of the pump and 9 is a cover member, the parts being secured together by fastening means A flexible diaphragm l3, impervious to gasoline, is clamped between the bodyand cover.

The cover is recessed on its lower side and, together with the diaphragm, forms the pump chamber. Vibratory movements of the diaphragm are used to vary the capacity of the pump 3 chamber and make the suction and discharge strokes.

The apertured center of the diaphragm is located upon a reduced part I! of a reciprocating rod or stem 19. On opposite sides of the diaphragm and also mounted on part H are discs 2| and 23. This assembly, together with suitable, washers 25, is held firmly on the stem i9 by a nut 21. 1

The body of the pump is formed with a partition 29 above which is a space for aspring 3| operating against the disc 23 to press the diaphragm upwardly, reduce the capacity of the pump chamber and thus make a discharge stroke. The rod or stem I9 is reciprocable with a suitable clearance through a tubular part 33. Part 33 functions as a dam to prevent any gasoline from passing through the clearance space around the stem IS in the event of leakage through a defective diaphragm. The clearance space (stem i9 is not guided by the opening through the 55 wall 33) prevents the sticking of the stem as a result of freezing of water vapor, which might occur in cold weather and interfere with the action of the pump. Preferably also a breather hole 35 is provided for the escape of any fuel collecting around the dam.

The discharge stroke of the pump is made by the spring 3| as stated above. The suction stroke is made positively (not resiliently) by means of mechanical .parts associated with the diaphragm and moved by a cam on the engine camshaft.- At 31 is shown the cam. It rocks lever 39 in a counter-clockwise direction upon a fulcrum pin 4| carried by the body I. The pin 4| is located in a chamber or cavity 43 beneath the partition 29 which chamber. is open and covers an opening in the engine crankcase, not shown, this being the usual construction with fuel pumps. The lever 39 has an arm 4! beyond its pivot 4| for engaging a link or lever extension 41, the link 41 having an eye 49 rotatably supported on pin 4|. When the arm 45 engages link 41, link 41 and lever 39 rotate as a unit about the pivot 4| under the pressure of thelcam. The end of link 41 and rod |9 are shaped to form an interlocking connection as shown in Fig. 3. This connection facilitates assembly and permits of a considerable range of relative rotation of the parts without endangering separation.

It will now be seen that the simultaneous counter-clockwise movement of lever 39 and link 41 under the influence of the cam pulls down upon the diaphragm, enlarges the capacity of the pump chamber, and thereby makes a suction stroke. It will be observed, however, that the extent of the discharge stroke is variable, being' dependent upon the developed pressure of the pump chamber. When the demand for fuel is less than the maximum capable of being delivered by the pump, the built-up pressure in the pump chamber balances the pressure of spring 3| and the diaphragm is not raised to its uppermost position. Under this condition arm 45 separates from link 41 and a subsequent suction stroke begins only when these parts again contact. It will therefore be seen that this is a variable stroke pump, the variation depending upon the built-up pressure in the pump chamber. For the purpose of holding the lever 39 against the cam during partial pump strokes and thereby prevent noise between the cam and the lever, spring 5| is seated about a boss 53 on r the pump body I and also about a boss 55 on an arm 51 of lever 39.

The cover 9 has a partition 59 to form the recess, the partition 59 and the diaphragm constituting the pump chamber as stated above. Above circular wall 63 and a substantially radial wall 65. An inlet passage 6? through the wall 63 and an outlet passage 69 also through the wall 63 are provided. Inlet passage 61 is for connection with the conduit from a fuel reservoir and opens into space 65. Outlet passage 59 is for connection with a conduit leading to the carburetor and it is in communication with an outlet valve (to be described) leading from the pump chamber and located in the wall 65. Substantially centrally of the cover and in the radial wall 65 is an inlet valve (to be described) afiording communication between the pump chamber and the upper part of chamber 6 I. Leading from the bottom of chamber ti and also in the wall of the chamber is a drain passage 69 closed by a manually operable valve H.

The inlet valve is constituted by a disc 1.3 seated against the lower end of a plug I5 threaded into an opening in the radial wall and located at the center of the cover 9. The disc I3 is held against its seat by a spring 11 located within an inner circular wall I9. A central opening BI communicates with the pump chamber. A longitudinal passage 83 and radial passages 95 aiford communication with the upper part of chamber 6|. A closure member 81 with a gasket 89 is clamped ,over the open top of cover 8. A screen BI is secured peripherally in position between the cover and closure. To secure the parts in position a plug I5 is provided with a reduced end threaded to receive a nut 93 which engages the outer surface of the closure and clamps the closure in position when threaded upon the end of plug I5.

For the outlet valve a valve seat 95 is located in an opening in the radial wall. A. valve disc 97 is held upon its seat by gravity and by a spring 99, the upper end of which is in abutment with a plug IUI threaded into an opening in the radial wall.

The drain plug 1| has a reduced end terminating in a valve I03. The valve seats as shown to close passage 69. It has an axial passage E05 extending throughout its length and a radial passage IIll afiording communication between the axial passage I05 and the reduced end, so that when the plug is turned to move the valve I03 from its seat liquid within the chamber BI may escape into the reduced end and through passages I01 and I05. By this arrangement water and other foreign matter may be removed from chamber El The operation will be understood from the above description; The fuel from the reservoir enters at 61 and is filtered by the filtering screen 9| as it passes from the lower portion of chamber GI to that part above the filter. It then passes through openings and 83 to the inlet valve. It then enters the pump chamber through passage 8 I. From the pump chamber it is forced through the outlet valve 91 to the pump discharge opening s9.

This construction has certain advantages over prior pumps. In this present pump the novel cover structure not only provides for carrying the valves but includes the chamber for the collection of. water and sediment, thereby avolng the need'of a separate filtration unit. It maintains a body of liqrdd fuel directly over the pump chamber, separated therefrom merely by a wall or partition 5%. As a result the heat which might tend to vaporize fuel in the pump chamher is in a large measure conducted to the liquid fuel in chamber bl. vaporization in the pump chamber is therefore avoided.

Figs. 4, 5, and 6 show a modification embodylI5 and III.

/ $104,446 the partition is a space iii formed by the outer ing the same essential features. This modification has been designed so that the discs of both inlet and outlet valves seat by gravity as well as under the influence of their springs, diifering in this respect from the former embodiment wherein the inlet valve was held to its seat by a spring against the action of gravity. Another difference is concerned with the accessibility of the valve mechanism which, in this case, is reached by removing plugs but without removing the equivalent of the closure member 81 in the form already described.

In this second form the body member 1 together with the operating mechanism may be the same as that shown in Fig. 1

The cover 9 is provided with two segmental chambers III and 3 divided by radial walls The filtering screen'SI' and the closure 81' are held-by fastening means M9 threaded into the central point of union of the walls H5 and Ill. The inlet passage 61 leads to the chamber III from which water and foreign matter may be drained by the same sort of drain plug 'II which has been described.

The fuel passes through the filter member 9| into the chamber H3 and from the chamber II3 it passes by way of a passage H9 to a space I2I beneath the inletvalve I23. This valve is formed by a seat (corresponding to seat 95 of Fig. 2), a valve disc 91', and a spring 99' seated against a threaded plug IOI accessible from the outside of the pump. It has been found desirable in forming the opening for the inlet valve seat to extend the passage -I2I into the pump chamber and to thereafter close the opening with a plug as at I25. This process of manufacture has been adopted to aid in assembling the valve seat 95 and to facilitate the securing of this 'seat to the cover. The cover 9' is formed with a passage I21 leading from a point above the inlet valve to the pump chamber as shown; in Fig. 4. The pump chamber communicates with the pump outlet at 69' by an outlet valve as shown in Fig. 6. This valve diflers in no essential respects from the valve shown in Fig. 2, and the same reference characters are used to represent the several parts. This form of the invention is much like the other, differing in that it provides for convenient accessibility to the valves and in that it employs valves both of which seat by gravity as well as under the influence of their springss The operation of both forms of the invention is the same. The fuel in each case enters a chamber which may be called the sediment chamber and from which foreign matter may be removed by the manually adjustable valve.

The fuel is then filtered and passed through the inlet valve to the pump chamber, and from the pump chamber it is dischargedthrough an outlet operatively connected with the diaphragm to -move the same and thereby operate the pump,

said cover having a fuel-receiving chamber, a

aroaeae first valve afifording a yielding inlet for the flow of fuel from the second chamber to the pump chamber and said cover having a second valve affording a yielding outlet from the pump chamher, said inlet valve comprising a movable valve disc, a plug extending axially into said cover and secured thereto and having at its end a seat for said valve disc, a closure for said fuel-receiving chamber, fastening means engaging said closure and adjustable, on said plug to maintain said closure in position.

2. In a fuel pump, a pump body, a cover, a diaphragm therebetween, said cover having a partition forming, together with the diaphragm, a pump chamber, means in said pump body and operatively connected with the diaphragm to move the same and thereby operate the pump, said cover having a fuel-receiving chamber, a

filter screen dividing said fuel-receiving chamber into first and second parts, said cover having a first valve afiording a yielding inlet for the flow of fuel from the second'chamber to the pump chamber and said cover having a second valve affording a yielding outlet from the pump chamher, said inlet valve comprising a movable valve disc, a plug extending axially into said cover and secured thereto and having at its end a seat for said valve disc, a closure for said fuel-receiving chamber, fastening means engaging said closure and adjustable on said plug to maintain said closure in position, said plug having therein a passage from the second part of the fuel-receiving chamber and communicating with the inlet valve.

3. In a fuel pump, a pump body, a cover, a

diaphragm therebetween, said cover having a partition forming, together with the diaphragm, a pump chamber, means in said pump body and operatively connected with the diaphragm to move the same and thereby operate the pump, said cover having a fuel-receiving chamber, a filter screen dividing said fuel-receiving screen into first and second parts, said cover having a first valve afiording a yielding inlet for the fiow of fuel from the second part of the fuel-receiving chamber to the pump chamber and said cover having a second valve affording a yielding outlet from the pump chamber, a plug extending axially into said cover, secured thereto and having an axial passage communicating with the pump chamber, one of said valves controlling said passage, a closure for said fuel-receiving chamber, and means associated withsaid plug to secure said closure in position.

, vABRAHAM M. BABITCH.

GORDON W. HARRY. 

